If I'm not mistaken, the Tech Artillery Platform had a barrel that changes pitch depending on where the target is. Don't take my word for it though.
The Commanche has that rocket pod thingy where each rocket fires at a particular point that is determined in the ini's. You could have the missles spread out that way.
As for having the missles bowing around the target, the Dragon tank's turret moves around when firing. You could have the MRLS do the same thing with the missles but just don't have the turret itself move. The missles could then home in to their particular destinations.
That may look a little odd with the missles coming out cockeyed from the turret.
